A test vessel device of the kind referred to above is described in the German technical journal "Dragerheft", Volume 303, page 15 (1976). The known test vessel device is used for calibrating gas measuring devices such as devices for determining hydrogen sulphide. Test-gas ampules are introduced into a flask for generating a test substance atmosphere. The ampules are mechanically destroyed before use of the test vessel device so that the content of the ampules can distribute in the flask volume. The sensor head of the test apparatus to be calibrated is introduced through an opening into the test vessel and it is intended that the corresponding concentration of hydrogen sulphide will be indicated by the calibrated device.
The known test vessel device has the disadvantage that the test ampules must be produced in advance with the greatest care, that is, the test gas must be mixed and filled into the ampules. The test gas in the ampules can deposit on the glass inner wall surface and thereby falsify the concentration of the test gas. Furthermore, it is inconvenient that the glass ampules must be first broken in the vessel after the sensor head has been introduced. The non-closable opening of the test vessel leads to a mixing of the test atmosphere of the vessel with the ambient air in the event that a long time duration elapses until the sensor head is introduced into the vessel. Furthermore, an intimate mixing of vapors which are heavier than air with the air disposed in the vessel is not assured in each instance. Accordingly, the condition cannot be prevented that the sensor head can be introduced into a region of the vessel wherein the desired test atmosphere is not yet present or thoroughly mixed.